Many satellites and other space vehicles, as well as some terrestrial vehicle applications, such as seagoing vessels, include a main source of electrical power and a standby, or backup, source of electrical power. The main source of electrical power may include one or more photovoltaic arrays, in the case of a satellite, or one or more engine-driven or turbine-driven generators, in the case of seagoing vessels. The standby electrical power source may include a battery, and may additionally include one or more energy storage flywheels, and/or one or more separate engine-driven or turbine-driven generators.
In systems that include one or more energy storage flywheels, the energy storage flywheels may each include a motor/generator. A motor/generator is an electrical machine that may be operated in a motor mode or a generator mode. In the motor mode, the motor/generator converts electrical energy to mechanical energy, and in the generator mode, the motor/generator converts mechanical energy to electrical energy. In the context of an energy storage flywheel system, the system may include a rotationally mounted flywheel that is coupled to the motor/generator. Thus, the motor/generator may be operated in the motor mode to spin up the flywheel and store energy therein. The motor/generator may also be operated in the generator mode to convert the stored energy in the flywheel to electrical energy.
Typically, the operation of the motor/generator in an energy storage flywheel system is controlled by a motor/generator controller. In most instances the motor/generator controller is located remote from the flywheel. Thus, the power cables that electrically couple the motor/generator to the controller may need to traverse some distance external to the flywheel system housing. Power cables can be a source of unwanted electromagnetic interference (EMI) to some circuit components, and can also be an unwanted source of weight. Moreover, the power cables may then need to be electrically coupled to the controller, which can in some instances be time consuming and costly.
Hence, there is a need for an energy storage flywheel system that addresses one or more of the drawbacks noted above. Namely, a system that reduces the length of power cables, which thereby reduces system weight and EMI emissions, and/or that alleviates the need to conduct time consuming electrical connections of the power cables to the controller circuits. The present invention addresses one or more of these drawbacks.